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Add lookup table for replication slot conflict reasons

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This commit switches the handling of the conflict cause strings for
replication slots to use a table rather than being explicitly listed,
using a C99-designated initializer syntax for the array elements.  This
makes the whole more readable while easing future maintenance with less
areas to update when adding a new conflict reason.

This is similar to 74a730631065, but the scale of the change is smaller
as there are less conflict causes than LWLock builtin tranche names.

Author: Bharath Rupireddy
Reviewed-by: Jelte Fennema-Nio
Discussion: https://postgr.es/m/CALj2ACUxSLA91QGFrJsWNKs58KXb1C03mbuwKmzqqmoAKLwJaw@mail.gmail.com
This commit is contained in:
Michael Paquier 2024-02-22 08:40:40 +09:00
parent 28f3915b73
commit 943f7ae1c8
3 changed files with 42 additions and 38 deletions
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47
src/backend/replication/slot.c
View File

@ -77,6 +77,22 @@ typedef struct ReplicationSlotOnDisk
ReplicationSlotPersistentData slotdata;
} ReplicationSlotOnDisk;
/*
* Lookup table for slot invalidation causes.
*/
const char *const SlotInvalidationCauses[] = {
[RS_INVAL_NONE] = "none",
[RS_INVAL_WAL_REMOVED] = "wal_removed",
[RS_INVAL_HORIZON] = "rows_removed",
[RS_INVAL_WAL_LEVEL] = "wal_level_insufficient",
};
/* Maximum number of invalidation causes */
#define RS_INVAL_MAX_CAUSES RS_INVAL_WAL_LEVEL
StaticAssertDecl(lengthof(SlotInvalidationCauses) == (RS_INVAL_MAX_CAUSES + 1),
"array length mismatch");
/* size of version independent data */
#define ReplicationSlotOnDiskConstantSize \
offsetof(ReplicationSlotOnDisk, slotdata)
@ -2290,23 +2306,26 @@ RestoreSlotFromDisk(const char *name)
}
/*
* Maps the pg_replication_slots.conflict_reason text value to
* ReplicationSlotInvalidationCause enum value
* Maps a conflict reason for a replication slot to
* ReplicationSlotInvalidationCause.
*/
ReplicationSlotInvalidationCause
GetSlotInvalidationCause(char *conflict_reason)
GetSlotInvalidationCause(const char *conflict_reason)
{
ReplicationSlotInvalidationCause cause;
bool found PG_USED_FOR_ASSERTS_ONLY = false;
Assert(conflict_reason);
if (strcmp(conflict_reason, SLOT_INVAL_WAL_REMOVED_TEXT) == 0)
return RS_INVAL_WAL_REMOVED;
else if (strcmp(conflict_reason, SLOT_INVAL_HORIZON_TEXT) == 0)
return RS_INVAL_HORIZON;
else if (strcmp(conflict_reason, SLOT_INVAL_WAL_LEVEL_TEXT) == 0)
return RS_INVAL_WAL_LEVEL;
else
Assert(0);
/* Keep compiler quiet */
return RS_INVAL_NONE;
for (cause = RS_INVAL_NONE; cause <= RS_INVAL_MAX_CAUSES; cause++)
{
if (strcmp(SlotInvalidationCauses[cause], conflict_reason) == 0)
{
found = true;
break;
}
}
Assert(found);
return cause;
}

22
src/backend/replication/slotfuncs.c
View File

@ -413,24 +413,12 @@ pg_get_replication_slots(PG_FUNCTION_ARGS)
nulls[i++] = true;
else
{
switch (slot_contents.data.invalidated)
{
case RS_INVAL_NONE:
ReplicationSlotInvalidationCause cause = slot_contents.data.invalidated;
if (cause == RS_INVAL_NONE)
nulls[i++] = true;
break;
case RS_INVAL_WAL_REMOVED:
values[i++] = CStringGetTextDatum(SLOT_INVAL_WAL_REMOVED_TEXT);
break;
case RS_INVAL_HORIZON:
values[i++] = CStringGetTextDatum(SLOT_INVAL_HORIZON_TEXT);
break;
case RS_INVAL_WAL_LEVEL:
values[i++] = CStringGetTextDatum(SLOT_INVAL_WAL_LEVEL_TEXT);
break;
}
else
values[i++] = CStringGetTextDatum(SlotInvalidationCauses[cause]);
}
values[i++] = BoolGetDatum(slot_contents.data.failover);

13
src/include/replication/slot.h
View File

@ -40,6 +40,9 @@ typedef enum ReplicationSlotPersistency
/*
* Slots can be invalidated, e.g. due to max_slot_wal_keep_size. If so, the
* 'invalidated' field is set to a value other than _NONE.
*
* When adding a new invalidation cause here, remember to update
* SlotInvalidationCauses and RS_INVAL_MAX_CAUSES.
*/
typedef enum ReplicationSlotInvalidationCause
{
@ -52,13 +55,7 @@ typedef enum ReplicationSlotInvalidationCause
RS_INVAL_WAL_LEVEL,
} ReplicationSlotInvalidationCause;
/*
* The possible values for 'conflict_reason' returned in
* pg_get_replication_slots.
*/
#define SLOT_INVAL_WAL_REMOVED_TEXT "wal_removed"
#define SLOT_INVAL_HORIZON_TEXT "rows_removed"
#define SLOT_INVAL_WAL_LEVEL_TEXT "wal_level_insufficient"
extern PGDLLIMPORT const char *const SlotInvalidationCauses[];
/*
* On-Disk data of a replication slot, preserved across restarts.
@ -275,6 +272,6 @@ extern void CheckPointReplicationSlots(bool is_shutdown);
extern void CheckSlotRequirements(void);
extern void CheckSlotPermissions(void);
extern ReplicationSlotInvalidationCause
GetSlotInvalidationCause(char *conflict_reason);
GetSlotInvalidationCause(const char *conflict_reason);
#endif /* SLOT_H */